Airlines and charter flight operators are urging officials to revamp management of aircraft movements through "unhelpful" Thai airports.
Affected parties are directing their ire towards so-called slot coordination, which they accuse of being inefficient, uncooperative and favouring Thai Airways International (THAI) at times.
The function of granting time slots for take-off and landing at big airports such as Suvarnabhumi and Don Mueang has been carried out under the umbrella of THAI.
"We often receive a 'no' when we ask for slots when we know that with a little cooperation, flexibility and understanding they could accommodate our requests," said an affected operator, who spoke to the Bangkok Post on condition of anonymity for fear of reprisal.
"Sometimes when we request a landing at, say, Phuket airport from the coordinators, they will turn us down, when a cross-check with Phuket tells us that the airport could handle us," the operator said. "Realistically, there are viable techniques to open a window to squeeze in some flights between the busy rosters, such as putting them in a holding pattern, rather than an outright rejection."
For one business aviation operator, those denials for flight slots are estimated to cost some 500 million baht a year as flights are aborted or turned away.
The affected parties are writing to Chula Sukmanop, director of the Civil Aviation Authority of Thailand (CAAT), for a meeting to discuss ways of tackling the problem.
The Airline Operators Committee, an industry body that represents 86 international airlines and 26 aviation service providers operating in Thailand, will act on behalf of the industry in the proposed meeting.
High on the revamp of slot coordination is reassigning the function away from THAI.
There are alternatives such as CAAT taking over the role, or delegating to a more neutral and service-minded body representing the industry-at-large, including Aeronautical Radio of Thailand Ltd, an air traffic controller founded by airlines.
The function of slot coordination has been handled by THAI for decades under government directives that have cited a lack of resources and expertise for performing such a role themselves.
The arrangement is outdated and looks odd from a global perspective, as the role is normally reserved for civil aviation regulators.
The slot problem involves the busier airports operated by Airports of Thailand, including Suvarnabhumi, Don Mueang and Phuket.